2015年12月1日 星期二

32 Bit JVM Memory

Max memory of 32 bit window is 4 GB. Q: How about 32 bit JVM?

A: According to the Oracle JVM FAQ, only 1.4 to 1.6 Gb heap memory can be get on 32 bit JVM.

Then, what is heap memory?

Explanation

"Java objects reside in an area called the heap. The heap is created when the JVM starts up and may increase or decrease in size while the application runs. When the heap becomes full, garbage is collected. During the garbage collection objects that are no longer used are cleared, thus making space for new objects."

JVM is Java Virtual Machine, which is s software machine that simulate what a machine does. HotSpot is an implementation of the JVM concept. There are other implementation of the JVM Specifaction , like JRockit, IBM J9. OpenJDK is a project of an opensource implementation of HotSpot (and many other things such as compiler, JDK APIs) ReferenceList of Java virtual machineshttps://en.wikipedia.org/wiki/List_of_Java_virtual_machines